1. Technical Field
The present invention is directed to a method and apparatus for automatically removing the build-up of particulate in a storage bin, such as a coal bunker, grain silo, and the like.
More particularly, the present invention is directed to a cutting tip device, and method of use, attached to a source of compressed gas via a hose, wherein the compressed gas is forced through the cutting tip device causing the device to gyrate in an erratic fashion about the hose and to strike the build-up, the force created thereby removing the build-up from the storage bin.
2. Background Information
Storage bins, such as coal bunkers and grain silos, are typically either cylindrical or rectangular, although other shapes are well known to those skilled in the art. Typically, storage bins include an inlet at or near the top of the bin for feeding the stored material into the bin. The stored material is removed typically through conical-shaped hoppers located at the bottom of the storage bin. As is known in the art, storage bins which house coal are typically referred to as coal bunkers; those that house grain are typically referred to as silos.
Typically, coal bunkers house several thousand tons of coal. The dimensions of a typical cylindrical coal bunker are about 70 feet in diameter and over 110 feet high; a typical rectangular coal bunker is 25 by 80 feet by over 50 feet deep. Turning now to FIG. 1, a typical prior art coal bunker is shown. The coal is fed into the bunker by means of a conveyor belt (not shown) positioned near top 21 of the coal bunker. The coal is removed from the bunker through conical-shaped hoppers, such as hopper 22, located at the bottom of the bunker. Through use, coal tends to build up along side walls 23 of the bunker, thereby reducing the effective capacity of the bunker.
Turning now to FIG. 2, a typical pattern of coal build-up along the interior walls of the coal bunker is shown. Build-up 24 reduces the effective capacity of the bunker. Additionally, the build-up near opening 25 can cause coal flow out of the bunker to stop due to the restriction caused by the build-up. This condition, typically referred to as a "rat hole", not only halts the flow of coal from the coal bunker, but also halts the production of steel should the bunker be on-line in a steel plant.
Should the coal bunker develop the rat hole, the maintenance and/or production supervisor in the coal plant will attempt to clear it so that production can continue. Although it is possible in some applications to use the contents of a different coal bunker, other applications require the coal stored in the specific coal bunker to be used due to the specific composition and/or mixture of the coal, or the like.
Generally, the rat hole is attempted to be cleared manually by jack hammers, pick axes, shovels, and the like. It has also been known, albeit infrequently, to employ a stream of water in an effort to clear the rat hole. However, any coal cleared by this method must be scrapped. Water contaminates the coal and renders it unseless; wet coal cannot be used even if placed into a pre-burner.
Thus, coal bunkers are cleaned on a periodic basis as a means of preventive maintenance. As is known in the art, prior art methods of cleaning the build-up are directed to sending a crew of workmen into the bunker to manually remove the build-up, usually by jack hammer, pick axe, and the like. The crew of workmen are typically lowered into the bunker from the top and safety lines are attached to the workmen to help prevent accidents. However, despite the safety lines attached to the workmen, this method is quite dangerous. Should a large portion of build-up break from the wall, and should a workman get caught in the falling debris, the weight of it can drag the workman down, despite the safety lines. It is well known and documented that many lives have been lost throughout the years due to this cleaning process, in spite of safety lines.
The problems associated with coal bunkers are also inherent with grain silos. Prior art devices are known in the art for helping induce the flow of material through grain silos when build-ups or bridges occur. (A bridge is formed when the material emptied from the bottom of a storage bin forms a void at its angle of repose, the gravitational weight of the material above the bridge being insufficient to overcome the friction along the surface area of the void when the material is at or near its angle of repose.) For example, as shown in U.S. Pat. No. 3,525,445 issued to Barger, herein incorporated by reference, a grain silo is shown for housing soybean meal. One of the problems with soybean meal is that it sticks to the interior walls of the storage bin, thereby preventing the flow of the mal therethough. Barger includes a series of inflatable hoses along the side walls of the storage bin which are inflatable to help the particles of soybean meal stuck to the side of the wall to dislodge, eventually exiting the hopper at its bottom. The inflatable hoses are rigidly attached near the top and bottom opening of the silo, and attached near the side walls of the conical-shaped hopper with a spring device which allows the hose, when inflated, to move away from the silo wall, creating an incline for the meal to slide down and breaking it up from the sides of the silo. The spring device causes the hose to return to the side wall one it is deflated. In U.S. Pat. No. 3,337,094 issued to Houston, herein incorporated by reference, a plurality of air-tight tubes run throughout the interior of a grain silo and are attached at the exterior of the silo to an air pump. When a bridge forms in the grain silo, the air pump is activated causing the air tubes to inflate. Due to the plurality of tubes located within the grain silo, at least one of the tubes should intersect the bridge formed in the silo. When that tube is inflated, the angle of repose is broken, and the gravitational weight of the material above the bridge further breaks down the bridge, restoring the flow of the grain through the silo. Although both Barger and Houston work well in grain environments, such devices would not be adequate in environments where the particulate of the build-up is more compact and heavy, such as in a coal bunker.